Laboratory Studies
See the list below:
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In evaluating the patient with sialadenitis, steps should be taken in the following order: history, physical examination, culture, laboratory investigation, radiography, and if indicated, fine-needle aspiration biopsy (see History and Physical).
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Laboratory investigations should begin with culture of the offending gland (if possible, prior to the administration of antibiotics).
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Blood cultures should be obtained in the patient exhibiting bacteremia or sepsis.
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As a rule, needle aspiration of a suspected abscess is not indicated.
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Routine electrolytes and complete blood cell count with differential should be obtained to assess for any evidence of dehydration or systemic infection.
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If a diagnosis of autoimmunity is entertained, serum analysis for antinuclear antibody, SS-A, SS-B, and erythrocyte sedimentation rate should be conducted.
Imaging Studies
Numerous radiologic techniques are available in submandibular imaging. Deciding which study to obtain first is often difficult. Examination selection should be based in part on the suspected cause of the problem. The authors' institution tends to begin with plain radiography, followed by the use of computed tomography scanning with combined sialography.
Radiography
Of all the radiologic examinations available, one of the simplest is conventional plain radiography. [5] Anteroposterior, lateral, and oblique intraoral occlusal views are used. This technique is particularly valuable in evaluating the presence of calculi, which are radio-opaque in approximately 70% of cases. These radiographs are limited in that they do not provide any information about the ductal system or soft tissues.
Sialography
Sialography can be used to evaluate sialolithiasis or other obstructive entities, as well as inflammatory and neoplastic disease. In this technique, a water-soluble medium such as meglumine diatrizoate is injected into the Wharton duct and lateral, oblique, and anteroposterior plain radiographs are obtained in order to assess the ductal arborization. Contraindications for this test are iodine allergy and acute sialadenitis.
Any filling defects (eg, calculi), retained secretions (eg, chronic sialadenitis), stricture formation (eg, inflammation), extravasation (eg, Sjögren disease), or irregularly contoured borders (eg, neoplasm) are noted.
Ultrasonography
Ultrasonography can be used to differentiate between solid versus cystic lesions of the gland. It can also be used to differentiate intrinsic from extrinsic disease and can be helpful in identification of abscess formation. A 2009 study by Bozzato et al determined that application of ascorbic acid (vitamin C) as a contrast agent can aid in the ultrasound assessment of obstructive sialadenitis of the parotid and submandibular glands. [6, 7]
A study by Omotehara et al indicated that ultrasonography is effective in the diagnosis of immunoglobulin G4–related sclerosing sialadenitis (IgG4-SS), with ultrasonography showing the submandibular gland to have a significantly greater longitudinal diameter and thickness in patients with IgG4-SS than in controls. In addition, a rough contour to the gland was found in 62.9% of the patients, versus 8.3% of the controls. Moreover, in an examination of internal echo textures, patients showed multiple hypoechoic nodule patterns or diffuse hypoechoic patterns, in contrast to controls, who were found to have only homogeneous echo textures. Additionally, significantly higher color Doppler signaling was observed in cases of IgG4-SS than in controls. [8, 9]
In an examination of the parotid and submandibular glands, a study by Li et al suggested that ultrasonography may also be helpful in posttreatment follow-up of IgG4 sialadenitis, finding that the treated glands decreased significantly in volume and that their internal echoes showed greater homogeneity. [10]
A study by Larson et al indicated that in terms of identifying sialoliths intraoperatively in patients with chronic obstructive sialadenitis, surgeon-performed ultrasonography has positive and negative predictive values of are 94% and 91%, respectively. [11]
CT scanning
Computed tomography (CT) scanning is an excellent modality in differentiating intrinsic versus extrinsic glandular disease. It is also extremely valuable in defining abscess formation versus phlegmon. It is limited in evaluating the ductal system unless combined with simultaneous sialography.
MRI
Magnetic resonance imaging (MRI) is of little utility in sialadenitis or sialadenosis. It does not allow evaluation of the ductal system, and it is not helpful in defining calcifications. It is an excellent tool for soft tissue definition and is invaluable in instances of suspected neoplasia.
PET/CT scanning
A retrospective cohort study by Takano et al indicated that 18F-fluorodeoxyglucose (FDG) positron emission tomography/CT (PET/CT) scanning may, when combined with serologic and clinical evaluation, be able to diagnose IgG4-SS. The investigators found that in 98% of patients with IgG4-SS, FDG uptake was increased in the submandibular gland. The diagnostic sensitivity, specificity, and accuracy of high FDG uptake by the submandibular gland in combination with a serum IgG4 level of 135 mg/dL or higher were reported to be 96.9%, 90.0%, and 86.4%, respectively. [12]
Procedures
See the list below:
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Fine-needle aspiration and biopsy
Open biopsy of the lip should be considered when the diagnosis of Sjögren disease is contemplated.
If suspicion of a solid neoplasm masquerading as sialadenitis is significant, a fine-needle aspiration with biopsy should be undertaken. The management and differential diagnosis of submandibular neoplasms is beyond the scope of the current discussion.
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Submandibular calculus.
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Sialogram with stenosis secondary to chronic sialadenosis.
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Submandibular abscess and associated Ludwig angina.
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Submandibular neoplasm.
